Inside Treviso's Duomo, which was modified during the 19th century, is the Malchiostro Chapel. There you'll find an Annunciation by Titian (1520) and frescoes by Pordenone (1484–1539), including an Adoration of the Magi. The crypt has 12th-century columns. Bring a handful of coins for the coin-operated lights that illuminate the artwork. To the left of the Duomo is the Romanesque Battistero di San Giovanni (from the 11th to 12th century), which is probably quite similar in style to the medieval Duomo. It's open only for special exhibitions.
Piazza del Duomo, Treviso, Veneto, 31100, Italy